In order to adapt to the lack of oxygen and cold in the alpine region. The most obvious characteristics of Tibetans are high nasal bones and large nostrils, which are caused by lack of oxygen and cold in alpine regions. Tibetan men's faces are mostly Chinese characters, which are divine, with developed masseter muscles on both cheeks, high cheekbones, narrow triangular eyes and many squints. Tibetan women have round faces, many Chinese characters, sharp noses and thin lips. Tibetans are not so fat, and older women are much thinner.